diff --git a/pkgs/servers/sql/postgresql/ext/timescaledb.nix b/pkgs/servers/sql/postgresql/ext/timescaledb.nix
index d674ccb7024c..eb02b05e5dc4 100644
--- a/pkgs/servers/sql/postgresql/ext/timescaledb.nix
+++ b/pkgs/servers/sql/postgresql/ext/timescaledb.nix
@@ -16,6 +16,7 @@ stdenv.mkDerivation rec {
   src = fetchFromGitHub {
     owner  = "timescale";
     repo   = "timescaledb";
+    # some branches are named like tags which confuses git
     rev    = "refs/tags/${version}";
     sha256 = "0j8fbhf69q0074c02ilzdrhwc1ciyw6dq48217xxv274df2lcxzd";
   };